1. Field of the Invention
The present invention relates to an automatic calibration process for electronic grinder-doser apparatuses of coffee in beans provided with an electronic weighing device, for the periodic control of the quantity of actually ground coffee and the consequent re-setting of the grinding times associated with the required dose weight in grams; the invention also relates to an electronic grinder-doser apparatus intended to implement said process.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The invention finds particular application in the industrial sector of professional bar equipment for making espresso coffee; furthermore, the invention applies to any electronic apparatus for grinding organic products which requires the periodic adjustment of the grinding times.
In general, professional machines for making espresso coffee, which are conventionally called coffee machines, are widely known, which are substantially characterized by a body comprising a boiler which generates hot water and steam sending them to one or more dispensing units in order to cross a corresponding number of filter-holding bowls containing the ground coffee, said bowls being hooked under each dispensing unit, hanging therefrom. In this way the hot water, crossing said filter-holding bowl, takes the aromas contained in the previously charged coffee powder or micro-granules.
Also known is said filter-holding bowl, which is an essential component in the coffee making process, and which consists of a body shaped as a cylindrical container with a funnel-shaped bottom and side hooking tongues, open on the upper part, which contains a filter selected depending on the specific quantity and type of coffee to be made; said bowl is generally provided with a side grip shaped as a cylindrical handle with horizontal development, protruding with respect to the body of the bowl, which allows the operator to easily hook it to said coffee machine and also, before that, to fill the filter with the coffee powder in a specific machine intended to grind it and dose it with precision. Said filter-holding bowl, in particular, must be filled with the exact quantity of coffee powder depending on the number of doses; generally, the bowls used in the professional sector allow to prepare one or two doses simultaneously for each bowl.
Therefore, said grinder-doser is essential in professional catering services, such as in bars and cafés, since it is an apparatus which allows to pass from roasted coffee in beans to powder in micro-granules which, pre-dosed, is necessary for the correct preparation of the usual cup of coffee, preserving its aroma. Downstream of the machine body, which grinds the coffee beans falling from the upper cone, there generally is a container which collects the coffee powder in micro-granules, below which is said bowl supporting element, which sometimes is guided by rails in order to be positioned correctly for the filling of the desired dose. Professional coffee grinding-dosing devices, conventionally known as grinder-dosers, are mainly subdivided into standard types and automatic types, wherein the first have a lever switch of the slide valve type which substantially leaves to the user the control of how much and how to grind the coffee, while the latter are provided with buttons and/or sensors which automatically control dispensing upon reaching such a threshold.
It is known that such electronic grinder-dosers have the advantage of limiting the operations by the operator who, sequentially, only has to position the bowl containing the filter corresponding to the pre-selected dose and then select the pre-selected grinding dose by activating the corresponding control, generally an electromechanical or electronic touch switch. Generally, in these apparatuses the quantity of coffee related to one or two doses, that is to say, for one or for two cups of espresso coffee, is previously pre-set by setting on the machine the parameters corresponding to the duration of grinding, that is to say, to the time of motor operation which is necessary to dispense the desired weight of ground product.
The operators of the sector also know that in high-level professional activity, as for example occurs in cafés and in restaurants, it is extremely important to adjust the grinding time with precision in order to obtain the exact quantity, in weight, of ground coffee since this is variable depending on the granulometry and on the type of coffee used, on the wear of the machine and, in particular, on environmental conditions among which humidity and temperature; therefore, it basically occurs that the duration of grinding is fixed, as it is set with the setting of the apparatus, while the dispensed dose is from time to time greater or smaller with respect to the desired weight, depending on said parameters. As a consequence, in these cases, the professional operator intervenes periodically on the setting of the grinder-doser, even several times a day, manually modifying by progressive approximations the duration of said operating grinding in order to obtain the exact weight of ground and dispensed coffee.
Therefore, it has been observed that the conventional and known systems for adjusting the dose weight in grams are little suitable for a professional activity which includes the frequent preparation of espresso coffee wherein, in particular, the product in beans is ground and dispensed in the respective filter-holding bowl respecting the exact dose weight in grams, said dose weight in grams being set directly or by means of the corresponding grinding time; therefore, such settings are pre-arranged by setting the grinder-doser according to the operator's specific requirements. In more detail as to the known and conventional solutions of control and adjustment of the actual dispensed dose, in particular, we recall various systems for weighing the ground product, being of the manual type and separate from the grinding phase, that is to say, as a periodic control sampling, or being of the automatic type and simultaneous to grinding; for example, one should remember the solutions as in documents GB594414 (Valerino), U.S. Pat. No. 4,789,106 (Weber), JPH07141560 (Masayuki), U.S. Pat. No. 6,155,158 (Anson), WO20100071390 (Vazquez Palma et al.), WO2005063100 (Malykke).
Finally, among the recently proposed solutions for facilitating daily operations in the professional sector, we have observed a wide spreading of various technologies for the automatic detection of objects or devices, in order to identify them or also to collect information about them, depending on the specific field of application; in particular, the technology of automatic recognition based on radio frequency, also known by the acronym RFID (Radio Frequency Identification) is widespread and has also been recently proposed in the industrial sector of bar equipment. Among the automatic recognition systems for the controlled dispensing of the correct dose, we would like to recall for example the advantageous solution as in TV2014A000113 (Fiorenzato) which provides an accessory device of automatic recognition of the filter-holding bowl by a coffee grinder-doser, being made up of an emitter apparatus emitting a radio-frequency identification signal and of a reader apparatus which detects and processes said signal in order to automatically dispense in the filter of the bowl the corresponding dose of ground coffee, for example for one or two cups, without manual selection. The emitter apparatus is made up of a fastening ring applicable to the handle of the bowl which supports a passive transponder of the RFID Tag type; the reader apparatus is made up of an RFID antenna, parallel to said RFID Tag, and of the relative RFID control card which is directly connected to it via cable and is also connected to the logic control unit of the grinder-doser for said automatic dispensing.
For the purpose of determining the prior art related to the proposed solution, a conventional check was made, searching public archives, which has led to find some prior art documents, among which:
D1 U.S. Pat. No. 5,462,236 (Knepler)
D2 U.S. Pat. No. 6,783,089 (Lassota)
D3 U.S. Pat. No. 5,522,556 (Knepler et al.)
D4 Baratza Forte, operation manual, 2013 (www.baratza.com)
D5 WO2013015801 (Rego et al.)
More specifically, D1 proposes a grinder-doser intended to calculate the weight of the desired dose as a function of grinding time in such a way that the operator, by means of a particular electronic calibration circuit, which is also interfaced with the logic control unit of the grinder-doser, manually inserts the weight of the actually ground dose in order to correct its setting.
D2, D3 and D4 propose electronic weighing systems which are constructively and electronically integrated in the grinder-doser in such a way as to directly detect the weight of the dispensed product, including the operatively associated container, and interrupt grinding upon reaching the predetermined weight; the weighing device is of the scale type with a horizontal plate on which the container has to be placed, with single extensometers as in D2 or with a central load cell as in D4, or is of the type with a side arm lever and an opposite load cell with respect to the container, as in D3.
D5 describes a device for measuring and displaying the exact quantity of ground coffee dispensed in a portafilter basket, in a coffee grinder-doser of the professional type, measuring the weight variation from the support of the basket; this device is of the electronic type and comprises a remote display for displaying the measured value and also comprises a particular portafilter basket equipped with buttons with digital user interface.
Therefore, it is reasonable to consider as known:                an apparatus of the coffee grinder-doser type comprising means for dosing the quantity of ground and dispensed coffee, wherein said means consist of manual lever devices or, alternatively, electromechanical devices, in such a way as to select the dispensing in one or two doses;        an apparatus of the coffee grinder-doser type, wherein the coffee powder is dispensed directly in the filter-holding bowl positioned in a supporting fork below the dispenser;        an apparatus of the electronic coffee grinder-doser type for professional use, wherein the dispensing of the desired quantity of coffee in weight, that is to say, the dose weight in grams, is fixed as it is previously pre-set by calculating the corresponding grinding time;        an apparatus of the electronic coffee grinder-doser type for professional use, wherein the dose weight in grams is measured during the actual dispensing as the coffee is weighed directly with its operatively associated container by means of an integrated weighing device which is connected to the logic control unit in order to automatically interrupt grinding upon reaching the previously pre-set weight;        a control and calibration system of the dispensed dose, for coffee grinder-dosers based on the setting of the grinding time, which provides the taking of an actually ground dose as a sample to be weighed separately in order to manually make the changes to the setting of the machine, by progressive approximations, or to manually insert the detected weight in an interposed interface circuit which carries out the calculation and the adjustment of the logic control unit.        
Drawbacks
Most of the above-described solutions aim at overcoming the known difficulties experienced every day by professional operators in obtaining from the grinder-doser the exact quantity of ground coffee; in general, it has been observed that the conventional solutions based on the taking and on the detection of the weight of a sample dispensing in order to calculate the corrections to be made to the setting of the apparatus are slow, uncomfortable and also imprecise, since many approximations are necessary before obtaining the desired result. In practice it has been observed that a common external scale involves several manual operations, also with a high risk of errors, that is to say, substantially independent with respect to the grinder-doser as it is not connected to the logic control unit; in particular the most evolved solutions, as for example in D1, provide the addition of a complex electronic calibration circuit which interacts with said logic unit acting as an interface with the user, who must carry out the weighing and insert the data manually in such a way that said circuit is able to act on the logic unit of the grinder-doser.
In the solutions which weigh the product during dispensing, as for example in D2, D3 and D4, a problem has been found, which is intrinsically linked to the tolerances of the weighing devices and which makes such solutions little effective. In particular, we have observed that in order to dynamically measure with precision variations in a weight of a few grams, generally between 7 and 7.5 grams in the case of a single dose of ground coffee, it is necessary to have an extremely accurate high-sensitivity weighing device, for example an electronic load cell with extensometers, which is thus unsuitable for the strong vibrations which the internal motor of the grinder-doser transmits to the whole body of the apparatus, thus making the weighing value not very reliable and also possibly decalibrating the system.
Furthermore, it has been observed that the solutions of control of the ground dose having a heavy container, that is to say, with a considerably greater tare with respect to the content, and also with an asymmetric and protruding shape which must be handled with care, are thus unsuitable for detecting a few hundredths of a gram, as for example in D5 wherein the portafilter basket is weighed separately on a small-sized separate device which is also provided with electronic interface; for a professional use, such a solution is expensive, fragile, uncomfortable in use and inaccurate in results.
Therefore, from the above considerations it can be stated that, since they are not known yet, it would be extremely desirable for professional operators to find effective solutions of automatic calibration of grinder-dosers also equipped with an electronic weighing device intended to detect slight weight variations, to eliminate the manual taking and weighing operations and automatically carry out the detections and the adjustments, by calculating and autonomously re-setting times also compensating for the variables which affect dispensing; in particular, it can be stated that, since they are not known yet, it would be extremely desirable for professional use to find automatic calibration processes and grinder-dosers intended to implement them which allow to frequently carry out said adjustment of the grinding time with great accuracy in such a way as to obtain exactly the desired dose weight in grams.
Considering all the above, there is the reasonable need for the companies of the sector to find some innovative solutions for overcoming the above-described drawbacks.